Parseltongue isn't Unbreakable Vow, it doesn't prevent people from changing their mind. Any attempt from Harry to abuse the promise like that will probably make Voldemort reconsider and no longer allow to name new persons for the same "class" of powers (like, early in the year, he said things like "no more body parts" when Harry was enumerating lots of body parts he could use to kill someone).
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 113.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
IMPORTANT -- From the end of chapter 113: